Tension arm



y 29, 1952 Y B. B. scoTT ETAL TENSION ARM Filed July 28, 1949 lvwven'bors. Ben} amin B. Sccjixt George FfGreen@ b I gfzzdwf H Their A'btowne gb Patented July 29, 1952 c UNITED ST ES PRICE-71 J "TENSION j Benjamin'B. Scott and George FJGreen'e, T'So'henectady, N. Y., assignors to 'Gen'er'akElectric Company, acorporation of New York 1 Application July 28, 1949,, Scrial'No. 10.7.2616

i This invention relates to winding machines, more-specifically to means for maintaining a predetermined tension in the wire as it is fed to the support on which it is beingwound and has for its object simple and reliable means for maintaining a predetermined tension uniformly while the wire is fed at nonuniform and high speeds sistan'ceis varied in accordance with ali'near or nonlinear function of the movement of anelectric contact removable over bared turns on one edge of the card. As these cards are rotated on the winding machine and the wire wbund in them, the speed of the wire is nonuniform, varyin in accordance with a complex sine function. Moreover the wire speed may momentarily drop to zero, or may reverse with reverse movement of the wire. When the wire is fed directly from the wire supply reel and its associated tension-producing means, uniform tension can be maintained only at very low winding speed because of the inertia of the supply reel and tensionmaintaining means. By passing the wire over a pulley mounted on a cantilever spring the speed can be increased somewhat, but when a critical speed is reached undampecl oscillations occur in 1 Claim. (o1.: 242--45) the pulley with resulting breakage of the wire. v

Moreover, the tension in the Wire is nonuniform and reaches values in excess of the yield point of the wire resulting in significant adverse changes in wire electrical properties including unit resistance.

In carrying out our invention in one form we pass the wire over a pulley mounted on the end of an arm having a counterweight on its other end. This counterweight is adjustable along the arm to provide the required tension and also adjustable in a direction at right angles to the arm in the plane of movement of the arm to prevent oscillation of the arm at high'speeds.

For a more complete understanding of our insuitable speed as by an electrici-motor "(not shown) From asupply reel 4 ithe wireipasses over a pulley-fi mounted ona-pivot'pin B secured to asuppo'rt l and-then over a guidesipulley't' on the-endof 'a straight tens'ion arm' 9 pivoted'ion the pin 6. Suitable w-ire tension m'aintaini-ng means is con-nected' to'the shaft "I 0' on 'which the reel 4 is secured,which tension'means may-be anelectric torque-motor10a, orr a drag element of the hydraulic, magnetic or'friction type.

For the purpose 0f counterbalancing the arm 9, we providea weight 1 I adjustably'mounted on an arm 12 which, in turn, is adjustably mounted on the arm-9 on theside-of *t'he'pivot? 6=opposite in an aolj-lis-i'ed 'po'sition on the arini2 'EbyZa c'lamping screw l3 and th'e-a'rm1 2-is securedcat' its upper end unadjusted position 'on the arm i9' by means criazeiampm'grserew l'fls 'As sli'own, the arm [2 extends downward from the arm 9 at right angles thereto and to the pivot 6 and in the plane of movement of the arm 9. The combination of weight H and arm [2, may be characterized below as a counterweight device.

Prior to the actual winding of a card but with the wire attached to the card 2, the arm l2 with the weight ll secured thereto is adjusted along the arm 9 with the torque motor applying the desired tension to the wire until the arm 9 is horizontal and the arm 12 secured in position by the screw [4. Then the card is rotated at the maximum desired winding speed and, while thus winding wire, the weight I l is adjusted along the arm l2 until the swing of the arm 9 is uniform for each card revolution and no inertia shock can be felt in the pin 6. It will be noted that adjustment of the weight on arm l2 varies the distance of the weight from the pivot 6 and, therefore, varies the inertia damping effect of the weight. Moreover, when the arm 9 is moved,

counterclockwise, the pulley 8 moving upward, by the counterbalanoing weight ll momentarily to take up slack in the wire, the weight M 'moves downward and inward toward a vertical plane passing through the axis of the pivot B for reduction in the counterbalancing effect of the weight and, therefore, reduced tension in the wire. When the arm 9 is moved clockwise in response to a momentary increase in wire tension, the opposite effect occurs, the weight ll moving outward to increase its counterbalancing effect and increase the wire tension. In each case, the variation in the effectiveness of the counterbalancing weight is in a direction to reduce the swing of the arm 9 and, therefore,'in-

duce the return of the arm 9 back to the horizontal position. We have found that the oifset position of the weight H with respect to the arm 9 causes the weight to absorb tension shocks in the wire to permit acceleration and deceleration of the reel 4 by the wire during the winding operation with wire tensions below the elastic limit of the wire. In a typical machine provided with our invention a nickel-chromium-iron wire having a diameter of .00225 inch has been wound at speeds of 200 R. P. M.

It will be understood that in a complete winding machine the guide pulley 8 is moved along the axis of the shaft 3 at such speed as properly to space the wire turns on the card 2. Preferably, the support I is thus moved. Such a machine is described and claimed in a copending application, Serial Number 664,471, filed on April 24, 1946 by John R. Moore for Variable Resistor Winding Machine and assigned to the same assignee as this invention.

Reverse movement of the wire, i. e., the wire is retrieved momentarily upon each turn of the card 2 when one end or a portion of the card lies wholly on one side of the axis of rotation of the card, as illustrated by the portion I5 of the card 2. The shape of the card 2 is governed by the desired resistance variation function as an electric contact (not shown) is moved over bared turns on the straight edge l6 of the card.

While we have shown a particular embodiment of our invention, it will be understood, of course, that we do not wish to be limited thereto since many modifications may be made and we therefore contemplate by the appended claim to cover any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

A tension device for a wire-winding machine comprising a wire-tension arm, a pivot supporting said arm at an intermediate point thereof, a first wire-guide pulley on one end of said tension arm, a second wire guide pulley mounted on said pivot, a wire-supply reel, wire-tension means connected to said reel for maintaining a predetermined tension in a wire supplied from said reel over said pulleys, a counterweight device adjustably positionable on said tension arm on the side of said pivot opposite said first pulley for selection of desired static tensions, said counterweight device including a downwardly extending second arm having a counterweight vertically adjustably positionable thereon for selection of desired tension variation characteristics as a function of angular displacement of said wire-tension arm.

BENJAMIN B. SCOTT. GEORGE F. GREENE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 261,415 Abel July 18, 1882 686,010 Webster Nov. 5, 1901 1,395,830 Jones Nov. 1, 1921 2,002,011 Horton May 21, 1935 2,104,809 ODowd Jan. 11, 1938 FOREIGN PATENTS Number Country Date 17,123 France Apr. 5, 1913 712,921 France Aug. 3, 1931 

